RFID device with changeable characteristics

ABSTRACT

An RFID device includes a first, relatively permanent portion and a second alterable or inactivatable portion. Upon the occurrence of some predetermined event, the second portion and/or its coupling to the first portion is physically altered, inactivating it. The first portion may itself be an antennaless RFID device that may be read at short range, and the second portion may be an antenna that, when coupled to the first portion, substantially increases the range at which the first portion may be read. The second portion may be configured to be altered or inactivated by any of a variety of predetermined events, such as involving physical, chemical or electrical forces, performed either on the RFID device, or upon an object to which the RFID device is coupled.

This application is a division of U.S. application Ser. No. 10/886,831,filed Jul. 7, 2004, which claims priority under 35 USC 119(e) to U.S.Provisional Application No. 60/485,313, filed Jul. 7, 2003. Both of theabove applications are herein incorporated by reference in theirentireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of radio frequency identification(RFID) tag and label detection systems, and to methods of detecting RFIDtags and labels.

2. Description of the Related Art

Radio frequency identification (RFID) tags and labels (collectivelyreferred to herein as “devices”) are widely used to associate an objectwith an identification code. RFID devices generally have a combinationof antennas and analog and/or digital electronics, which may include forexample communications electronics, data memory, and control logic. Forexample, RFID tags are used in conjunction with security-locks in cars,for access control to buildings, and for tracking inventory and parcels.Some examples of RFID tags and labels appear in U.S. Pat. Nos.6,107,920, 6,206,292, and 6,262,692, all of which are herebyincorporated by reference in their entireties.

As noted above, RFID devices are generally categorized as labels ortags. RFID labels are RFID devices that are adhesively or otherwise havea surface that is attached directly to objects. RFID tags, in contrast,are secured to objects by other means, for example by use of a plasticfastener, string or other fastening means. Nevertheless, RFID devicesare referred to herein somewhat interchangeably as “tags” or “labels.”

RFID devices include active tags and labels, which include a powersource, and passive tags and labels, which do not. In the case ofpassive tags, in order to retrieve the information from the chip, a“base station” or “reader” sends an excitation signal to the RFID tag orlabel. The excitation signal energizes the tag or label, and the RFIDcircuitry transmits the stored information back to the reader. The“reader” receives and decodes the information from the RFID tag. Ingeneral, RFID tags can retain and transmit enough information touniquely identify individuals, packages, inventory and the like. RFIDtags and labels also can be characterized as to those to whichinformation is written only once (although the information may be readrepeatedly), and those to which information may be written during use.For example, RFID devices may store environmental data (that may bedetected by an associated sensor), logistical histories, state data,etc.

In activating, reading, and/or detecting RFID devices, radio frequency(RF) fields are generally sent over a relatively long range, that is,over intervening free space. Thus detection of devices is accomplishedover a significantly-sized region, and spatial discrimination in readingand detection of devices may be difficult.

One concern that has been raised regarding RFID devices is that theirability to be read over relatively long distances may implicate privacyconcerns for people having objects with RFID devices attached thereto orotherwise coupled thereto.

In addition, RFID devices may include commercially-sensitive informationthat is utilized in channels of commerce in supplying products to an enduser. It may be desirable that this information rendered ungatherable ormore difficult to gather after the product reaches the end user.

It will be appreciated that concerns about possible tracking or otherprivacy-related issues, or issues involving undesired dissemination ofcommercially-sensitive information, may inhibit some users fromemploying RFID devices. Accordingly, it will be appreciated that itwould be desirable for RFID devices to avoid the above problems.

SUMMARY OF THE INVENTION

According to an aspect of the invention, an RFID includes at least aportion that has alterable characteristics.

According to another aspect of the invention, an RFID device has a firstportion and an inactivatable second portion. The device may be read at agreater range when the second portion is not inactivated, than when thesecond portion is inactivated.

According to yet another aspect of the invention, an RFID deviceincludes a first portion and an inactivatable second portion, whereinthe inactivatable second portion includes an antenna. Even with thesecond portion inactivated, the RFID device may be read at short range.

According to a further aspect of the invention, an RFID device has afirst portion and an inactivatable second portion, wherein the secondportion may be inactivated by contact with a suitable solvent. Thesolvent may be a substance, such as water, that dissolves at least partof the inactivatable second portion, such as a substrate, and/or amaterial placed upon the substrate.

According to a still further aspect of the invention, an RFID deviceincludes an inactivatable portion that is inactivated by contact with asuitable material having pre-determined characteristics. For example,the second portion may be inactivatable by exposure to water above acertain temperature, while not being inactivated by exposure to waterbelow the given temperature. As another example, the inactivatableportion may be inactivated by exposure to water having an additive, suchas a detergent, while not being inactivated by exposure to water withoutthe additive.

According to another aspect of the invention, an RFID device includes afirst portion and an inactivatable second portion, wherein the firstportion is sealed to prevent contact with a solvent, abrasion, or othercontaminants and/or potentially damage-producing situations.

According to another aspect of the invention, an RFID device isconfigured so as to change characteristics upon laundering of an object,such as a garment, to which the RFID device is attached or otherwisecoupled.

According to a still further aspect of the invention, an RFID deviceincludes a first portion and an inactivatable second portion, whereinthe inactivatable second portion may be physically separated from thefirst portion along a predetermined boundary.

According to a further aspect of the invention, an RFID device includesa first portion and an inactivatable second portion wherein the secondportion is inactivated by normal use of an object to which the RFIDdevice is coupled.

According to a still further aspect of the invention, a radio frequencyidentification (RFID) device includes a first portion and a secondportion operatively coupled to the first portion. The second portion isalterable upon occurrence of a predetermined event. The device hasdifferent electrical characteristics depending on whether the secondportion is altered.

According to another aspect of the invention, a method of associatinginformation with an object includes: coupling an RFID device to theobject, wherein the RFID device is configured to change electricalcharacteristics during expected use of the object; and transferring theobject to a user.

According to yet another aspect of the invention, a method of at leastreducing accessibility of information associated with an object includesreceiving an object with an RFID device coupled thereto, wherein theRFID device is configured to have read characteristics of the RFIDdevice changed by occurrence of a predetermined event associated withordinary use of the object; and changing read characteristics of thedevice by using the object in an ordinary way.

According to still another aspect of the invention, a radio frequencyidentification (RFID) device including a transponder chip; and anantenna coupled to the chip. Coupling between the chip and at least partof the antenna is alterable upon occurrence of a predetermined event.The device has different electrical characteristics depending on whetherthe coupling between the chip and the at least part of the antenna isaltered.

To the accomplishment of the foregoing and related ends, the inventioncomprises the features hereinafter fully described and particularlypointed out in the claims. The following description and the annexeddrawings set forth in detail certain illustrative embodiments of theinvention. These embodiments are indicative, however, of but a few ofthe various ways in which the principles of the invention may beemployed. Other objects, advantages and novel features of the inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the annexed drawings, which are not necessarily according to scale:

FIG. 1 is a plan view of an RFID device in accordance with the presentinvention;

FIG. 2 is a cross-sectional side view of a prior art interposer or strapthat may be part of the device of FIG. 1;

FIG. 3 illustrates the RFID device of FIG. 1 incorporated into agarment;

FIG. 4 is a plan view of one embodiment of the device of FIG. 1, adevice with a soluble substrate;

FIG. 5 is a plan view of another embodiment of the device of FIG. 1, adevice with a soluble portion of an antenna;

FIG. 6 is a plan view of yet another embodiment of the device of FIG. 1,a device with one or more soluble antenna links;

FIG. 7, is a plan view of an embodiment of the device of FIG. 1 thatinclude a sealing material;

FIG. 8 is a plan view of an embodiment of the device of FIG. 1 that isconfigured to be severed;

FIG. 9A shows the device of FIG. 8 attached to a container;

FIG. 9B shows another example of the device of FIG. 8 attached to acontainer;

FIGS. 10-12 are views of various objects with RFID devices of thepresent invention coupled thereto, to be subjected to various physicalforces during use of the objects;

FIG. 13A is a plan view illustrating an RFID device of the presentinvention with a protective coating applied to a portion thereof;

FIG. 13B is a plan view of a portion of an RFID device of the presentinvention that has electrical characteristics that are altered uponstretching of the device;

FIG. 14 is a schematic illustration showing electrical coupling betweenan RFID device of the present invention, and an object having a circuit;

FIG. 15 is a plan view of an RFID device in accordance with the presentinvention, having fusible electrical connections;

FIG. 16 is a schematic illustration of the device of FIG. 15,incorporated into a computer;

FIG. 17 is a plan view of an RFID device in accordance with the presentinvention, having an alterable RFID chip;

FIG. 18 is a schematic illustration of an RFID device having analterable RFID chip, incorporated into a mobile telephone;

FIG. 19 is a view of an RFID device in accordance with the presentinvention, incorporated in a battery-operated device; and

FIG. 20 is a view of a semi-passive RFID device in accordance with thepresent invention, having alterable characteristics.

DETAILED DESCRIPTION

An RFID device includes a first, relatively permanent portion and asecond alterable or inactivatable portion. Upon the occurrence of somepredetermined event, the second portion and/or its coupling to the firstportion is physically altered, inactivating it. The first portion mayitself be an antennaless RFID device that may be read at short range,and the second portion may be an antenna that, when coupled to the firstportion, substantially increases the range at which the first portionmay be read. The second portion may be configured to be altered orinactivated by any of a variety of tasks performed either on the RFIDdevice, or upon an object to which the RFID device is coupled. Examplesof ways in which the second portion may be inactivated include exposureto a suitable solvent, such as water used in a laundering process;tearing or otherwise physically separating the second portion from thefirst portion; other applications of physical force that may be part ofregular use of the object to which the RFID device is coupled; andapplication of electrical forces.

In further explanation of a broad overview of the invention, an RFIDdevice may include an electronic circuit such as an integrated circuit(also referred to herein as a chip), an antenna having one or moreantenna elements, and an electrical coupling or connection between theelectronic circuit and the antenna. The RFID device includes analterable portion that alters or disables function of the RFID deviceupon occurrence of some predetermined event. A “predetermined event”, asthe term is used herein, is defined as some event that is likely tooccur in normal transfer or use of an object to which the RFID device iscoupled, but is not likely to occur prior to such normal transfer anduse. A predetermined event may be a physical, chemical, or electricalevent. The alterable portion may be a soluble portion, for instance asoluble antenna portion, that is dissolved in the presence of somesolvent, for example in water or a water and detergent combination. Thealterable portion may be a portion of the electrical coupling thatchanges composition (and thus its electrical coupling characteristics)when exposed to a suitable reactant. The alterable portion may be aportion of the coupling or antenna that alters or changes electricalcharacteristics (such as by narrowing or breaking) when subjected to atensile force or an impact force. The alterable portion may include aportion that is severed or physically separated from the rest of theRFID device. The alterable portion that may include a portion that isconfigured to be altered in function by a suitable electrical event,such as by powering up of an electrical or electronic device which theRFID device is coupled to or which the RFID device is a part of. Theelectrical event may, for example, alter or disconnect portions of theantenna of the RFID device, or may disable or alter function of the chipof the RFID device.

Alteration of the alterable portion may cause the RFID device to becomefully non-functional (non-readable or non-detectable). Alternatively,alteration of the alterable portion may cause the RFID device tocontinue functioning, but with altered characteristics. For instance,the altered characteristics may include a reduction in the distance atwhich the RFID device may be read or detected. This may be done bydecoupling the RFID chip from the antenna, or by reducing the amount ofthe antenna that is effectively coupled to the RFID chip. Even when theRFID chip is decoupled from the antenna, the RFID chip may remaincoupled to an interposer or strap, which may allow short-range detectionof the RFID device.

The relatively-permanent portion of the RFID device may include anantennaless device, which may be read by a proximity detector. As usedherein, the term “antennaless” refers broadly to devices lacking anantenna that is viable for receiving RF energy for remote, long-rangereading. In characterizing antennaless devices, it is useful to comparethem with well-known antennaed structures. An example of a well-knownantenna structure is a dipole antenna with a good impedance matchbetween the antenna and an RFID chip. A good impedance match providesgood power transfer between antenna and chip. A dipole antenna has anantenna gain, relative to a perfect antenna, of approximately 2 dBi(decibels relative to an isotropic radiator—something that radiatesequally in all directions). In a perfectly-impedance-matched situation,all of the power received by the antenna will be transmitted to the RFIDchip.

Relative to structures described above having a perfect antenna or animpedance-matched dipole antenna, an “antennaless” structure willperform poorly. Such poor performance may in part be due to aninherently low antenna gain (due to small physical dimensions of thestructure relative to wavelengths of RF energy). Another factor in poorperformance of antennaless structures may be a poor impedance matchbetween the chip and connected conductors (such as conductive leads),which manifests itself as a further power loss. Thus in an antennalessRFID device there may be losses, relative to an RFID device, due tosmall size of conductive structures that could receive RF energy, and/ordue to poor impedance match, limiting efficiency of power transferbetween the conductive structures and a chip of the device.

An antennaless RFID device, as the term is used herein, is defined as adevice having a structure such that when it is placed in the far fieldof a transmitter (defined below), an RFID chip of the device that isattached to the structure will absorb −20 dB in power compared to animpedance-matched dipole antenna. Put in other words, the structure ofan antennaless device, when placed in the far field of an RFtransmitter, provides to an attached RFID chip 1% or less of the powerthat an impedance-matched dipole antenna would provide to the RFID chip.

An antennaless RFID device may be powered through use of a proximitylocator, a device that generates a short-range RF field, with relativelylow far-field RF radiation. The far field, as used herein, refers to adistance greater than about 15 mm from an RF-energy emitting device,such as device that emits UHF RF energy. Coupling of an RFID device inthe far field is also referred to as “long-range coupling.” The nearfield, where short-range coupling may occur, is defined as less thanapproximately 15 mm from an RF-energy emitting device. Placement of theRFID device in the near field is also referred to herein as placement ofthe device in “close proximity” to the proximity locator or parts of theproximity locator.

An example of UHF RF energy, referred to above, is RF energy in therange of 860 MHz to 950 MHz. However, it will be understood that a widevariety of other RF frequencies may be utilized, including frequenciesother than UHF RF frequencies. For instance, frequencies of about 2-3GHz may be utilized, although it will be appreciated that theshort-range-coupling outer range limit from the RF-energy emittingdevice may be reduced when higher frequencies are employed.

A proximity detector of locator for detecting the presence of antennaedor antennaless RFID devices may include two or more conductors thatcreate a suitable electrical field between the conductors or in thevicinity of the conductors. The conductors may be capacitively coupledto the RFID device to provide power to the RFID device, or to otherwiseinteract with the RFID device, allowing detection of devices in thevicinity of the electrical field.

Further information regarding proximity devices or locators may be foundin commonly-owned U.S. application Ser. No. 10/406,702, which is hereinincorporated by reference in its entirety.

Referring initially to FIG. 1, an RFID device 10 with changeablecharacteristics is shown. The RFID device 10 has a first portion 12 withrelatively permanent read characteristics, and a second portion 14,which is inactivatable or otherwise changes characteristics.

The first portion 12 includes a first portion substrate 18 with anantennaless device 20 such as a strap or interposer 22 thereupon. Theinterposer or strap 22 includes a chip 24 (also referred to as amicrochip) connected to conductive leads 26 and 28.

With reference now to FIG. 2, details of the interposer or strap 22 arenow described further. As stated above, the interposer or strap 22includes the chip 24 and the conductive leads 26 and 28. The leads 26and 28 operatively coupled to chip contacts 30 of the chip 24. The chip24 may be referred to herein in addition as an “electronic element.” Thechip 24 may include any of a variety of suitable electronic components,such as the circuitry described above for modulating the impedance ofthe RFID device 10.

The leads 26 and 28 may be completely made out of an electricallyconducting material, such as being made out of a metal foil.Alternatively, the leads 26 and 28 may include an electricallyinsulating material, for example being plastic coated with metal. Theinterposer or strap 22 may include an interposer substrate 34 that isattached to the leads 26 and 28. The interposer substrate 34 may be madeof any of a variety of suitable materials, for example, suitableflexible polymeric materials such as PET, polypropylene or otherpolyolefins, polycarbonate, or polysulfone. Alternatively or inaddition, the interposer substrate 34 may include a conductive material,such as a metal or a metal foil.

The interposer or strap 22 may be any of a variety ofcommercially-available interposers or straps. Examples include an RFIDinterposer or strap available from Alien Technologies, and theinterposer or strap marketed under the name I-CONNECT, available fromPhilips Electronics. Alternatively, the interposer or strap 22 may beother than a commercially-available interposer or strap.

The leads 26 and 28 may have a length of approximately 7 mm. Anantennaless RFID device with leads 7 mm long would be suitable forreceiving RF energy at very high frequencies, on the order of 20 GHz,but would not be considered an antenna within the definition usedherein.

More broadly, the leads may have a length of up to one-tenth of awavelength at the operating frequency, although, as stated earlier it isdesirable to minimize this for cost reasons. For example, a wavelengthof 327.8 mm corresponds to an operating frequency of 915 MHz. Leads forsuch an operating frequency may have a length up to 33 mm.

It will be understood that the terms “interposer” and “strap” are notrestricted to the embodiment just described. The terms “interposer” and“strap,” as used herein, refer broadly to devices that include amicrochip or other electronic circuitry, coupled to conductive leads.The conductive leads may be connected to contacts on the microchip orother circuitry by any of a variety of suitable methods.

The second portion 14 includes a second portion substrate 40 upon whichan antenna or portion of an antenna 42 is located. The antenna 42 iscoupled to the antennaless device 20 that is part of the first portion12. The antenna 42 then coupled to the antennaless device 20, enablesdetection of the RFID device 10 as longer ranges, relative to thedetection of the antennaless device 20 alone.

The second portion 14 may be inactivatable, or otherwise changed inoperating characteristics, upon occurrence of one or more predeterminedevents. The event may involve physical separation of the second portion14 from the first portion 12, such as by tearing, cutting, or severingalong a boundary 46 between the first portion 12 and the second portion14. Alternatively, as explained in greater detail below, a physical,electrical, or chemical process may be utilized to inactivate orotherwise change characteristics to the second portion 14. Examples ofvarious ways in which the second portion 14 may be inactivated orotherwise changed are described below.

The second portion 14 is described above as including the antenna 42. Itwill be appreciated that the inactivatable portion may be other than anantenna. For example, the inactivatable portion may be only part of anantenna, changing the range or other characteristics of the RFID device.The inactivatable portion may be one or components of the RFID device,such that the operating frequency of the RFID device is altered byinactivation of the inactivatable portion of the device. For instance,inactivation of the inactivatable portion of the device may cause thedevice operating frequency to change, say from 915 MHz to 2450 MHz.

It will be appreciated that a wide variety of alternatives may be madein the configuration of the RFID device 10. For example, the RFID device10 may have any of a variety of suitable antenna arrangements, and mayhave a wide variety of other suitable structures and/or configurations.

As another alternative, the RFID device 10 may be configured so thatremote readability of the device is totally destroyed by inactivation ofthe inactivatable portion, such as the second portion 14. Such a device,when inactivated, may be detectible and/or readable only by contactmethods, i.e., by methods involving actual physical contact with thechip 24.

Referring to FIG. 3, the RFID device 10 may be coupled to a washableitem, such as a piece of clothing 50, for example, being on or within alabel 52 of the article of clothing 50. For example, the label 52 may bea thermally transferable label. The second portion 14 of the device 10may be configured so as to be inactivated when the article of clothing50 is laundered.

As one example of such a device, illustrated in FIG. 4, the secondportion substrate 40 may include a soluble material 60 that dissolveswhen exposed to a suitable solvent. For example, the soluble substrate60 may be a water-soluble material, such as rice paper or anothersuitable material, that dissolves or otherwise breaks down when exposedto water. When the washable item 50 is laundered or otherwise exposed towater, the soluble substrate 60 would break down, thereby destroying theintegrity of the second portion 14, and causing the antenna 42 toseparate. However, at least part of the first portion 12, such as thepart including the antennaless device 20, may be configured to remainactive, and readable through use of a proximity locator or detector, asdescribed above.

The label 52 may include other layers, such as a printable layerdisplaying text and/or graphics. Soluble layers such as the solublesubstrate 60 may be laminated to the printable layer in such a way sothat the text and/or graphics are viewable even after the solublesubstrate 60 has been dissolved.

Another alternative is shown in FIG. 5, wherein the antenna 42 includesat least a portion 61 that is made of a soluble conductive material thatis soluble in water or another suitable solvent. Examples of suitablesoluble conductive materials include soluble inks, such as thosedescribed in U.S. Pat. Nos. 5,286,415 and 5,855,820, both of which areherein incorporated by reference in their entireties. The antenna 42 maybe formed by printing conductive ink on the substrate 40 of the secondportion 14.

In a specific embodiment, illustrated in FIG. 6, the antenna portion 61may be one or more soluble conductive links 62. Removal of the solubleconductive links 62 may deactivate the antenna 42 or decouple theantenna 42 from the first portion 12. Alternatively, the solubleconductive link 62 may be suitably located so as to merely alter theelectrical characteristics of the antenna 42.

The first portion substrate 18 and the second portion substrate 40 mayinclude suitable materials, for example, suitable flexible polymericmaterials, such as those described above for the substrate 34 of thestrap 22 (FIG. 2).

For the embodiment shown in FIG. 4, the first portion substrate 18 maybe of a different material from that of the second portion substrate 40.Alternatively, or in addition, with reference to FIG. 7, a sealingmaterial 64 may be used to seal all or part of the first portion 12 toprotect the interposer or strap 22, for example, from exposure to thewater or other solvent that is used to deactivate the second portion 14.The sealing material 64 may be a suitable epoxy or adhesive material.

It will be appreciated that the RFID device 10 that may be partiallyinactivated by washing could be used advantageously in a variety ofsituations in a garment. For example, the fully-operational RFID device10, with the active second portion 14, may be used to track the garment50, prior to sale, at relatively long range, such as in a far-fieldregion. For example, long-range detection may be desirable in terms ofinventory control tracking, facilitating gathering information forstreamlining purchasing operations, and/or for theft prevention. Havingthe second portion 14 deteriorate during laundering may make the RFIDdevice 10 less intrusive, for example, by reducing size and/or stiffnessof the device, thereby improving comfort of the user of the garment 50.In addition, removing or changing the long-range detectability of theRFID device 10 may be advantageous to aid in maintaining privacy of thewearer or user of the garment 50. Still, it may be desirable to havemeans of short-range tracking of the RFID device 10, even when thesecond portion 14 has been inactivated. Such short-range detection ofthe RFID device 10 may aid in authenticating the garment 50, forexample, in processing returns of the garment. For instance, a proximitylocator or detector may be used to read information from the antennalessdevice 20 in a near-field region, to confirm that the garment 50 isbeing returned to the same store from which it was purchased.

Another alternative is for the device 10 to be configured so as todeteriorate substantially completely upon occurrence of a predeterminedevent. For example, the entire substrate of the device may be made of awater-soluble material, such as rice paper. Some small portion of thedevice, such as an interposer or strap, may remain after thepredetermined event, such as laundering of a garment to which the RFIDdevice 10 is coupled. Configuration of the device so that substantiallythe entire substrate of the device is made of a water-soluble materialis a particularly advantageous version in regard to the advantage notedearlier, i.e. reducing the size and/or stiffness of the device in orderto improve the comfort of the user of a garment carrying the device.

It will be appreciated that many variations are possible in terms ofmaterials and/or solvents utilized. For example, the second portionsubstrate 40 and/or the material of the antenna 42 or other structuresin the second portion 14, may be configured to inactivate or otherwisechange characteristics in response to contact to a material other thanwater. For example, the second portion 14 may be configured to becomeinactive in response to contact with materials used in dry cleaningprocedures, such as carbon tetrachloride. Alternatively, the secondportion 14 may be configured to be inactivatable by exposure to water ofa certain minimum temperature or to water containing a suitabledetergent. It will be appreciated that such a feature may be utilized toreduce the probability of undesirable, accidental or deliberateinactivation of the long-range readability of the RFID device 10, or asa way of confirming that proper laundering of the garment 50 has takenplace. For example, garments for use in a hospital may be configured tobecome partially or totally inactive only when washed in a minimumtemperature of water. Long-range detection of laundered garments may beused to identify garments that have not been properly laundered, due tosuch garments retaining such long-range readability of RFID devices.

Water solubility of water-soluble material may be changed by changingthe molecular weight of a polymer utilized in a soluble ink, for exampleby controlling crosslinking of the polymer. By increasing crosslinkingof the polymer by a suitable amount, such as by a several-fold increasein molecular weight, the water-soluble material may become substantiallyinsoluble in cold water, but still may remain soluble in hot water. Theaforementioned U.S. Pat. Nos. 5,286,415 and 5,855,820 disclose methodsto graft water-soluble and water-insoluble hydrophobic polymer. Watersolubility can be controlled by the amount of hydrophobic polymer in theresultant graft copolymers.

Another alternative is a second portion 14 that includes a conductivematerial that has its conductivity characteristics altered by exposureto a predetermined substance or chemical, thereby changing the readcharacteristics of the RFID device. For example, the second portion 14may have an antenna 42 may of different conductive materials, one ofwhich is water-soluble (hydrophilic) and the other of which isinsoluble, either by being a hydrophobic material or being coated toprevent contact with water. The water-soluble material may be on top ofthe insoluble material, so that exposure to water reduces the thicknessof the antenna 42. Alternatively, the water-soluble material may beadjoining and in contact with the insoluble conductive material, so thatexposure to water decreases the width of the antenna 42. It will beappreciated that a variety of other configurations may be obtained thatgive the antenna 42 changed electrical characteristics upon occurrenceof a triggering event.

As another alternative, the RFID device 10 may include a portion that isdissolved by exposure to a chemical composition that is mixed andactivated during use of the product. For example, the RFID device 10 maybe placed on a barrier that is ruptured during activation of a device,such as a fluorescent device.

It will be appreciated that it may be possible to configure the RFIDdevice 10 so that such changes in characteristics are reversible, so asto make the RFID device 10 re-usable as a detector of exposure to thechemical or substance. For example, exposure to a first substance couldalter characteristics from a first state to a second, different state,while exposure to a second substance could alter the characteristics ofthe device back to the first state.

Many alternatives are possible for the location of a soluble substrateor substrate portion, or a soluble conductive link. For example, solubleconductive material may be used for a conductive link between theinterposer or strap 22 and the rest of the RFID device 10. Removal ofsuch soluble material may thereby electrically isolate the interposer orstrap 22. As another alternative, a soluble adhesive may be used tophysically couple the interposer or strap 22 to the rest of the RFIDdevice 10. Dissolution of the adhesive may physically separate theinterposer or strap 22 from the RFID device 10.

The RFID device 10 may include soluble structures other than antennas,removal of which (by contact with a suitable solvent) may change theoperating characteristics of the RFID device 10. For example, a solubleadhesive may used to attach one part of the device 10 (such as aninterposer or strap) to another part (such as the substrate with theconductive pattern (antenna) thereupon.

It will be appreciated that the RFID device 10 with a soluble portion orportions may be utilized in a wide variety of applications where anobject is washed as part of its normal use, or otherwise comes intocontact with a suitable solvent.

FIG. 8 shows an RFID device 10 with a physically-separable secondportion 14, which may be inactivated by physically separating it fromthe first portion 12 along a severing line 68. The severing may be anyof a variety of physically separating processes, such as cutting ortearing. The severing line 68 may be an area that is perforated, scored,or otherwise configured to make the severing easier, and/or to encouragesevering at the desired location along the severing line 68.

Alternatively or in addition, the severing line 68 may correspond to avisual indicator such as a printed line, to aid in locating the severingin a proper place. In addition, the RFID device 10 may have instructionsthereupon, in words and/or symbols, directing an end user or otherperson to sever the RFID device 10 along the severing line 68, tophysically separate the second portion 14 from the first portion 12. Forexample, the RFID device 10 may have instructions such as “CUT HERE”written thereupon, indicating to the user the severing line 68 where thesecond portion 14 is to be separated from the first portion.

The severing line 68 is shown in FIG. 8 as a straight line. However, itwill be appreciated that the severing line 68 may more broadly be aboundary of any shape.

FIG. 9A shows the RFID device 10 of FIG. 8 mounted on an item 70 thathas an opening seam 74, with the severing line 68 along the opening seam74. The RFID device 10 is severed along the severing line 68, therebyinactivating the second portion 14, by opening of the item 70 along theopening seam 74. Thus, the item 70 may be a box or other containerconfigured such that in order to conventionally open the container toaccess the inner contents, requires inactivating the second portion 14of the RFID device 10 thereupon. A consumer then may be required to cut,tear, or otherwise sever the RFID device, for example, incapacitatinglong-range readability of the RFID device, in order to open thecontainer.

The item 70 may be a box or a folder that contains an object or objectsinside. Alternatively, the item 70 may be an object that includes ahinged or other openable portion, such as with a compact disk playerwith an opening for receiving a compact disk, or a hinged portabletelephone that must be opened for operation.

FIG. 9B shows an alternative mounting for the RFID device 10 of FIG. 8,on a container 76 that has a removable top 78. The container 76 may be acontainer that has a screw-off or pull-off top 78, such as a containerfor holding perfume or medicines. The RFID device 10 may be adhered tothe container 76 with parts of the device 10 adhered to the top 78 and abody 79 of the container 76, with the device 10 configured relative tothe container 76 such that the severing line 68 of the device 10 isabout at the location where the top 78 meets the body 79. When thecontainer 76 is opened by separating the top 78 from the body 79, theRFID device 10 is severed, altering characteristics of the RFID device10. For instance, the distance over which the RFID device 10 may be readmay be reduced by the severing. Thus, once the product is used byopening the container 76, the RFID device 10 may be partially or fullyreduced in function, protecting privacy of a consumer or end user.

In addition, the RFID device 10 shown in FIGS. 9A and 9B may be employedas an anti-tampering device. The location of the RFID device 10 mayprevent opening of the item 70 or the container 76 without alteringoperation of the RFID device 10. Thus tampering prior to sale of theitem 70 or the container 76 may be detectable by an RFID reader mountedin a display unit, such as a shelf, or at a point of sale location, suchas a cash register. In addition, severing of the RFID device 10 may bedetected visually, by either a retailer or a consumer. Thus tamperingwith products may be discouraged by making such tampering easilydetectable.

FIGS. 10-12 illustrate those situations where the RFID device is placedon an object and is thereby subjected to various types of physicalforces encountered in ordinary use of the object. FIG. 10 shows the RFIDdevice 10 on an object 80, such as a compact disk or a centrifuge, thatmay be subjected to centrifugal forces 82 in ordinary use. FIG. 11 showsthe RFID device 10 on or as part of an object 90 that is subjected tostretching forces 92 during use. An example of an object 90 is a vehicletire that is stretched during installation on a vehicle wheel. FIG. 12shows an RFID device on an object, such as the sole of a shoe 100, thatis subjected to abrasive or other wearing forces during regular use. Inall of these configurations shown in FIGS. 10-12, the RFID device 10 maybe configured such that the second portion 14 is subject to change bythe physical forces encountered in use of the objects 80, 90, and 100,while the first portion 12 is less affected or unaffected by the variousphysical forces.

With regard to FIG. 13A, the device 10 may have a strengthening coating110 over at least part of the first portion 12, to provide strength orotherwise aid in protecting at least part of the first portion 12 fromdamage or other alterations due to physical force.

FIG. 13B shows a portion 111 of an RFID device 10 that has electricalcharacteristics that are alterable by stretching. The portion 110 has asubstrate 112 with a conductive trace 114 thereupon. The conductivetrace 114 may be a part of an antenna or other electrical connection.The substrate 112 may be any of a variety of suitable materials thatcould support a conductive trace, such as a conductive ink trace, andwould be sufficiently stretchable to allow alteration of the electricalcharacteristics of the conductive trace. One broad category of suitablesubstrate materials is unoriented polyolefins, for example having athickness from about 25 and 200 μm (microns). Another example of asuitable material for the substrate 114 is a suitable paper layer. Theconductive trace 114 may be a silver ink trace printed on the substrate112. When the portion 110 is in its unstretched state, the electricalresistance of the conductive trace 114 may be on the order of a fewohms.

When the substrate 112 is slightly (elastically) stretched, theresistance of the conductive trace 114 may be substantially unchanged.However, once the elastic limit of the substrate material is exceeded,and the substrate 112 significantly deforms, the resistance of theconductive trace 114 rapidly, non-reversibly increases. Putting a weakportion in the substrate 112, such as an indention or perforations 116,may concentrate the stretching forces, controlling and/or enhancing thechange in the resistance of the conductive trace 114.

Turning now to FIG. 14, the RFID device 10 may be configured such thatthe second portion 14 is inactivated or changed by occurrence of anelectrical event. For example, the RFID device 10 may be coupled toobject 130, such an electrical device, such that operation of circuitry140 of the object 130 passes electrical power through all or part of thesecond portion 14 of the RFID device 10, inactivating or otherwisealtering function of the second portion 14. For example, passing currentthrough the second portion 14 may burn out all or a portion of anantenna 42 on the second portion 14.

It will be appreciated that a wide variety of electrical operations maybe used to inactivate or otherwise alter function of the second portion14. FIGS. 15-20 give a few examples of RFID devices 10 that may beinactivated, or have their operating characteristics changed, byoccurrence of an electrical event. FIG. 15 shows a device 10 that has anantenna 142 that has antenna elements 144 with fusible sections 146 thatbecome open circuits when power is supplied to the antenna by a powersupply 150. The power supply 150 may represent power transmitted to theantenna 142 by operation of an object to which the RFID device 10 iscoupled, or into which the RFID device 10 is incorporated. The objectmay be, for example, any of a wide variety of electrical devices.

The power supply 150 may be coupled to elements of the antenna 142 by RFchokes 154, which are conductive traces with desired characteristics.The antenna elements 144 may be coupled to an RFID chip (transponder)156, and also may be linked together by a bypass inductor 160, whichlinks the elements 144 around the RFID chip 156.

Once power is supplied to the antenna elements 144 by the power supply150, such as by operation of the object, the fusible portions 146 of theantenna 142 are melted or otherwise rendered as open circuits. Thisdecouples the RFID chip 156 from at least portions of the antennaelements 144, changing characteristics of the RFID device 10.

As noted above, the power supply 150 may be a power supply of a deviceor object, which automatically directly applies a DC voltage to the RFchokes 154 when operation of an electrical circuit is commenced. It willbe appreciated that a wide variety of alternatives may be possible forthe power supply 150. For example, the power supply 150 may be aswitched supply, such that a user may be given the option of whether toapply power to the RFID device. The power supply 150 may be auser-controlled switchable power supply. For instance, as shown in FIG.16, the RFID device 10 may be coupled to a port 161 of a computer 162that is under control of the computer. When a user first starts thecomputer 162, the user is given an option to apply power to the RFIDdevice 10, to disable or reduce readability of the RFID device 10. Itwill be appreciated that this option allows users to retain enhancedreadability of the RFID device 10 by leaving full function of the RFIDdevice 10 enabled. This may be desirable for corporate or other users,for instance, to allow tracking and identification of frequently-stolenitems, such as laptop computers.

FIG. 17 shows a configuration of the RFID device 10 wherein power fromthe power supply 150 is applied directly to the RFID chip 156. Whenpower is supplied to the RFID chip 156 from the power supply 150, someor all of the functionality of the RFID chip 156 may be destroyed.

The power supply 150 may be configured to provide a suitable voltage andcurrent to alter or destroy functionality of the RFID chip 156. Forexample, the power supply 150 may be a 12-volt power supply used to runinternal components of an electrical or electronic device.Alternatively, the power supply 150 may provide a higher voltage, suchas voltages on the order of hundreds of volts, used to powerelectroluminescent backlights on telephones and computers.

According to another alternative, illustrated in FIG. 18, the RFID chip156 of an RFID device 10 may be coupled to an antenna 142 of a mobiletelephone 170. Prior to powering up of the mobile telephone 170, thechip 156 may engage in long-range communicatation with RFID readers, viathe antenna 142. However, applying the relatively high RF power of thepower supply 150 of the mobile telephone 170 to the antenna 142 maydisable or alter functionality of the RFID chip 156, disabling thereadability of the RFID chip 156 at long ranges. As an alternative, theRFID device 10 may be configured such that the application of high RFpower from a mobile telephone disables a fusible link, similar to theprocess described above with regard to the device of FIG. 15.

FIG. 19 shows a configuration that allows testing of a battery-poweredelectrical or electronic device 180 without impairing or destroyingfunctionality of an RFID device 10 that is configured to change or ceasefunction during normal operation of the battery-powered device 180. Abattery compartment or holder 182 provides a pair of first contacts 184and 186 couplable to one pole 188 of the battery 190, and a secondcontact 194 couplable to an opposite pole 196 of the battery 190. In anormal operating condition, one of the first contacts 184 and the secondcontact 194 are coupled to an electrical or electronic device 198 toprovide power to the device 198. Examples of such electrical orelectronic devices include radios, CD players, and digital cameras. Theother first contact 186 and the second contact 194 are coupled to theantenna 142 of the RFID device 10, to disable the RFID device 10 or toalter the functional characteristics of the RFID devices. This changingof the characteristics of the RFID device 10 may be accomplished usingthe methods described above with regard to the embodiments shown inFIGS. 15 and 17. Thus placement of the battery 190 in the battery holder182 alters or destroys functionality of the RFID device 10.

Nonetheless, it will be appreciated that it may be desirable to testfunctioning of the electrical or electronic device 198, whilemaintaining unaltered the functioning of the RFID device 10. This may beaccomplished by somehow blocking connection of the battery 190 to thefirst contact 186 that is coupled to the RFID device 10. One way to dothis is to use a special battery for testing the electrical orelectronic device 198, a battery that does not have a pole that connectswith the first contact 186. Another way of preventing prematurede-activation of the RFID device 10 is to provide a special adaptor tobe placed on the battery 190 or the battery holder 182 during testing,to prevent contact between the pole 188 of the battery 190 and the firstcontact 186 that is coupled to the RFID device 10.

FIG. 20 shows a semi-passive RFID device 10 that is configured to bepowered by a low-current power supply 210. Such a low-current powersupply 210 may be a power supply in a device for keeping a real-timeclock or other components active even when a higher-current main powersupply 220 is off. The main power supply 220 is also coupled to the RFIDdevice 10 to de-activate or alter function of the RFID device 10 whenthe main power supply 220 is activated. This alteration of function maycome from a fusible link 222 between where the main power supply 220 iscoupled to an antenna 142 of the RFID device 10, and where the antenna142 is coupled to an electrical system ground 226. The low-current powersupply 210, the main power supply 220, and the system ground 226 arecoupled to the antenna 142 through respective RF choke sections 230,232, and 234.

The semi-passive RFID device 10 may have a longer range than passiveRFID devices that rely on a rectified RF signal for power. The detectionrange of such a semi-passive device may be up to 5 times that of apassive device.

The various types of RFID devices disclosed herein, with inactivatableor alterable portions that may be altered or inactivated by chemical,physical, or electrical processes, may be linked by a common concept,that of an RFID device that is altered or inactivated by eventsassociated with sale or other transfer of an item, and/or by eventsassociated with normal expected use of an item. Thus garments areexpected to be laundered, containers containing goods opened, vehicletires stretched during the mounting process, electrical devices poweredup, and shoes worn along their soles. As described above, RFID devicesmay be configured to provide alterable characteristics in each of thelisted situations, through a variety of mechanisms.

Although the invention has been shown and described with respect to acertain preferred embodiment or embodiments, it is obvious thatequivalent alterations and modifications will occur to others skilled inthe art upon the reading and understanding of this specification and theannexed drawings. In particular regard to the various functionsperformed by the above described elements (components, assemblies,devices, compositions, etc.), the terms (including a reference to a“means”) used to describe such elements are intended to correspond,unless otherwise indicated, to any element which performs the specifiedfunction of the described element (i.e., that is functionallyequivalent), even though not structurally equivalent to the disclosedstructure which performs the function in the herein illustratedexemplary embodiment or embodiments of the invention. In addition, whilea particular feature of the invention may have been described above withrespect to only one or more of several illustrated embodiments, suchfeature may be combined with one or more other features of the otherembodiments, as may be desired and advantageous for any given orparticular application.

1. A radio frequency identification (RFID) device comprising: atransponder chip; and an antenna coupled to the chip; wherein couplingbetween the chip and at least part of the antenna is physicallyseparable along a line of the device; wherein the device has differentelectrical characteristics depending on whether the coupling between thechip and the at least part of the antenna is physically separated; andwherein the device is unreadable at a distance greater than or equal toapproximately 15 mm from the device when the chip is physicallyseparated from the at least part of the antenna.
 2. The device of claim1, wherein the line is a severing line along which the coupling betweenthe chip and the at least part of the antenna is severable.
 3. Thedevice of claim 2, wherein the severing line includes scoring of thedevice.
 4. The device of claim 2, wherein the severing line includesperforation of the device.
 5. The device of claim 1, wherein the lineincludes a visual indicator.
 6. The device of claim 5, wherein thevisual indicator includes a printed line.
 7. The device of claim 1,wherein the device has instructions printed thereon regarding physicalseparation along the line.
 8. The device of claim 1, wherein, beforephysically separating along the line, the RFID device has an operatingfrequency in the UHF range.
 9. The device of claim 8, wherein, beforethe severing, the operating frequency is from 860 MHz to 950 MHz. 10.The device of claim 8, wherein, after the severing, the operatingfrequency is outside the UHF range.
 11. The device of claim 1, whereinphysically separating along the line reduces the amount of the antennathat is effectively coupled to the chip.
 12. The device of claim 1,wherein the chip is part of an antennaless device coupled to the atleast part of the antenna.
 13. The device of claim 12, wherein theantennaless device remains intact after physically separating, along theline, of the coupling between the chip and the at least part of theantenna.
 14. The device of claim 12, wherein the antennaless device,when placed a distance greater than 15 mm from an RF transmitter,provides to the chip 1% or less of the power that an impedance-matcheddipole antenna would provide to the chip.
 15. The device of claim 12,wherein the antennaless device includes an interposer that includes thechip and a pair of conductive leads attached to the chip.
 16. The deviceof claim 1, wherein physically separating along the line changes anoperating frequency of the device.
 17. The device of claim 16, whereinphysically separating along the line increases the operating frequencyof the device.
 18. The device of claim 1, wherein the chip is part of anantennaless device coupled to the at least part of the antenna.
 19. Thedevice of claim 18, wherein the antennaless device remains intact afterphysically separating the coupling between the chip and the at leastpart of the antenna.
 20. The device of claim 18, wherein the antennalessdevice, when placed a distance greater than 15 mm from an RFtransmitter, provides to the chip 1% or less of the power that animpedance-matched dipole antenna would provide to the chip.
 21. Thedevice of claim 18, wherein the antennaless device includes aninterposer that includes the chip and a pair of conductive leadsattached to the chip.
 22. A radio frequency identification (RFID) devicecomprising: a first portion that includes a transponder chip; and asecond portion that includes at least part of an antenna that is coupledto the chip; wherein the coupling between the chip and at least part ofthe antenna is physically separable along a boundary between the firstportion and the second portion; wherein the device has differentelectrical characteristics depending on whether the coupling between thechip and the at least part of the antenna is physically separated; andwherein the device is unreadable at a distance greater than or equal toapproximately 15 mm from the device when the chip is physicallyseparated from the at least part of the antenna.
 23. The device of claim22, wherein the boundary is a line.
 24. The device of claim 23, whereinthe line is a severing line.
 25. The device of claim 22, wherein thefirst portion includes a first part of the antenna, coupled to the chip;and wherein the second portion includes a second part of the antennathat is coupled to the first part of the antenna prior to physicalseparation along the boundary.
 26. A method of associating informationwith an object includes: providing a radio frequency identification(RFID) device, wherein the RFID device includes: a first portion thatincludes a transponder chip; and a second portion that includes at leastpart of an antenna that is coupled to the chip; wherein the couplingbetween the chip and at least part of the antenna is physicallyseparable along a boundary between the first portion and the secondportion; wherein the device has different electrical characteristicsdepending on whether the coupling between the chip and the at least partof the antenna is physically separated; and wherein the device isunreadable at a distance greater than or equal to approximately 15 mmfrom the device when the chip is physically separated from the at leastpart of the antenna; and coupling the RFID device to the object.